A planogram is a model that indicates how retail products should be placed on shelves to maximize sales and minimize wasted space. It defines which products go in which areas and quantities. There are different types of planograms including text-based for supermarkets, pictorial for apparel brands, and 3D models that visualize product location and quantity. Planograms are used to maximize space and sales through strategic cross-merchandising and identifying highest converting locations. They also help detect traffic flows and optimize visual and commercial product placement goals through research-backed minimum spacing between items.